Possible beta beam scenario(s) in the US

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Possible beta beam scenario(s) in the US

• Andreas Jansson
• Fermilab

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Outline

• This talk is far from a blueprint for beta beams
  at US labs!
• Attempt to look at how US machines could fit into
  a CERN-like scenario.
• Basic calculations to investigate which US
  machines could be utilized.

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CERN site study
Decay ring
Decay ring
Ions generated 2 1013 s-1 6He 8 1010 s-1 18Ne
1500 Tm
B?
B 5 T
B 5 T
L
2500 m
L
2500 m
ss
ss
?150
SPL
Ions stored 2 1014 6He2 9 1012
18Ne10 (simultaneously in 44 10ns bunches)
Decay
Decay
ISOL target
Ring
Ring
Ion source
SPS
SPS
ISOL linac
100 MeV/u
PS
PS
Storage ring RCS
?9.2
300 MeV/u
Slide from M. Lindroos et al
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CERN Intensities
Stage 6He 18Ne (single target)
From ECR source 2.0x1013 ions per second 0.8x1011 ions per second
Storage ring 1.0x1012 ions per bunch 4.1x1010 ions per bunch
Fast cycling synch 1.0x1012 ion per bunch 4.1x1010 ion per bunch
PS after acceleration 1.0x1013 ions per batch 5.2x1011 ions per batch
SPS after acceleration 0.9x1013 ions per batch 4.9x1011 ions per batch
Decay ring 2.0x1014 ions in four 10 ns long bunch 9.1x1012 ions in four 10 ns long bunch
Only b-decay losses accounted for, add efficiency
losses (50)
Slide from M. Lindroos et al
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Different CERN scenarios

• Original based on max SPS field, ?(He)150
  Nufact02.
• Both species in machine simultaneously, optimum
  at ?(He)60 and ?(Ne)100 Nufact03
• Higher energies, proposed ? 600 (upgraded SPS).
  Relaxes beam requirements hep-ph/0312068
• Low energy (nuclear physics) hep-ph/0303222

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Possible US sites
Only considering high energy beta-beams
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Possible US scenario
8 / 1.2 GeV SC Linac
Decay
Decay
ISOL target
Tevatron/ RHIC
Ring
Ring
Ion source
ISOL linac
Storage ring?
MI/AGS
FNAL/ AGS Booster
Note that both labs already have an RCS, as
proposed for CERN scenario. Both labs also have
plans for a SC proton driver linac ?
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Brookhaven machines
Machine Top Energy Ramp time Cycle time Harmonic Circumference
AGS Booster 8 GeV 1/15 s 2/15 s 1,2,3 208 m
AGS 31 GeV 0.5 s 1 s 6,8,12 807 m
RHIC 500 GeV 75 s 150 s 360, 2520 3800 m

• Energies are for protons
• Proposed 1.2 GeV Linac could be used for RI
  production

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Brookhaven machines II
Machine Gamma Average lifetime Estimated Decay Loss
AGS Booster 2.8 / 4.5 1.1 s / 2.9 s 4 / 2
AGS 10 / 17 3.7 s / 15.8 s 12 / 3
RHIC 83 / 139 43 s / 183 s 70 / 24
Values are for 6He2 / 18Ne10
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Some Brookhaven issues

• Acceleration efficiency (RHIC)
• Associated losses
• Low rep rate
• Top energies comparable to CERN SPS (or less)

Upgrade power supplies?
Could perhaps interleave RHIC rings to double
rep rate? Harmonic numbers also similar to
CERN ?
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Fermi machines
Machine Top Energy Ramp time Cycle time Harmonic Circumference
Booster 8 GeV 1/32 s 1/16 s 84 479 m
Main Injector 150 GeV 0.7 s 1.5 s 28, 588 3219 m
Tevatron 980 GeV 17 s 35 s 1113 6282 m

• Energies are for protons
• Proposed 8 GeV Linac could be used for RI
  production

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Fermi machines II
Machine Gamma Average lifetime Estimated Decay Loss
Booster 2.5 / 3.9 1 s / 3.6 s 2 / 0.6
Main Injector 50 / 83 13 s / 54 s 4 / 1
Tevatron 326 / 544 99 s / 423 s 13 / 3
Values are for 6He2 / 18Ne10
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Fermi machines III
Machine Max intensity per Tevatron cycle Avg. loss power W/m Duty factor
Booster 1.54 1013 /1.18 1013 0.3 / 0.3 1 (?)
Main Injector 1.52 1013 / 1.18 1013 0.12 / 0.14 3-6 (?)
Tevatron 1.32 1013 / 1.14 1013 1 / 1 50

• Values are for 6He2 / 18Ne10, calculated to
  yield
• 1 W/m on average in Tevatron (not based on ion
  production)

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Some Fermilab issues

• Loss sensitivity of Tevatron (how many RIs can it
  take all the way to top energy?).
• Relatively long acceleration cycle of Tevatron
  (lower rep rate than SPS).
• Activation and shielding of Booster (and other
  machines).
• all the non-CERN specific issues

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Decay ring

• CERN baseline version fits on site
• For higher gamma, site limits size (more space at
  BNL).
• What direction to experiment (Soudan too far
  away)?

CERN baseline, ?(He)150
Scaled to ?(He)320
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Observations

• Both BNL and Fermilab plan for proton drivers
  that could be used for RI production
• If RHIC can be made to ramp significantly faster,
  BNL site may be comparable to CERN for BB
• Main injector can get close to the proposed
  energies for running both HeNe simultaneously at
  CERN.
• Using the Tevatron, could achieve higher gammas !

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Studies needed for higher gamma

• Physics gain from going to Tevatron energies
  (?He320 and ?Ne540 ).
• Possible experiments and locations.
• Intensity and bunching factor requirements.
• More details on efficiencies, loss limits and
  intensity limits (i.e. can these requirements be
  met).
• Longitudinal gymnastics scheme (need new RF?).